Machining method for small corner structure of deep cavity in small area

Abstract

The invention belongs to the technical field of machining processes, and particularly relates to a machining method for a small-area deep cavity small-corner structure, which comprises the following steps: S1, drilling four holes of 4 millimeters in four corners of a magnesium alloy material by using a drill bit with the diameter of 4 millimeters to form R2 corners; s2, three holes are machined in the position, 0.5 mm away from the cavity wall, in the cavity through a 9-mm drill bit, and large allowance is removed; s3, a short end mill with the diameter being 8 mm and the length being 70 mm is used for roughing, and the machining depth is 40 mm; s4, a medium-length end mill with the diameter being 8 mm and the length being 100 mm is used for roughing, and the machining depth is 70 mm; and S5, a long end mill with the diameter being 8 mm and the length being 130 mm is used for roughing, and the machining depth is 100 mm. According to the method, materials can be rapidly removed, cutter connecting edges can be effectively avoided, the size precision of the cavity is higher, the surface quality is better, and the requirements of batch production and product assembly are met.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing technology, and in particular relates to a processing method for a deep cavity small corner structure in a small area. Background Art

[0002] For magnesium alloy material processing with deep cavities and small corners in small areas (refer to Figure 1 , Figure 1 The figure shows a magnesium alloy structural part). Traditional methods mainly include wire cutting and cavity milling. Wire cutting is a commonly used processing method and has certain advantages in processing parts with complex shapes. Cavity milling is more common in general cavity processing. The cavity is formed by rotating the milling cutter to remove material.

[0003] At present, although the wire cutting method can achieve a certain shape processing of the magnesium alloy structural parts, the processing efficiency is extremely low and it is difficult to adapt to the needs of mass production. At the same time, the characteristics of the magnesium alloy material lead to serious surface corrosion after wire cutting, affecting the performance and appearance of the parts. When using the traditional cavity milling method, when processing this deep cavity small corner structure, due to the difficulty in optimizing the tool path and cutting parameters, a large cutting edge will be generated in the cavity, resulting in poor surface quality of the parts, which cannot meet the accuracy and surface quality requirements required for product assembly. Therefore, a new processing method is urgently needed to overcome these problems in order to achieve efficient and high-quality processing of magnesium alloy deep cavity small corner structural parts. Summary of the invention

[0004] The object of the present invention is to provide a method for processing a deep cavity with a small corner structure in a small area in view of the above problems.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for processing a deep cavity with a small corner structure in a small area, the processing method comprising the steps of: S1. Use a 4 mm diameter drill bit to drill four 4 mm holes at the four corners of the magnesium alloy material to form R2 corners; S2. Use a 9 mm drill bit to drill three holes in the cavity at a distance of 0.5 mm from the cavity wall and remove the large excess; S3, use a short end mill with a diameter of 8 mm and a length of 70 mm to roughen, and the processing depth is 40 mm; S4, use a medium-length end mill with a diameter of 8 mm and a length of 100 mm to roughen, and the processing depth is 70 mm; S5, use a long end mill with a diameter of 8 mm and a length of 130 mm to roughen, and the processing depth is 100 mm; S6. Use a long end mill with a diameter of 8 mm to semi-finish the cavity, leaving a single-side allowance of 0.05 mm, and mill 20 mm in the depth direction each time; S7, use a long end mill with a diameter of 8 mm to fine mill the cavity, milling 15 mm in the depth direction each time; S8. Use a 4mm long end mill to finish mill the remaining part, using the forward milling and reverse milling method. First, forward milling with a cutting depth of 2mm to 3mm, and then the next forward milling with a cutting depth of 2mm to 3mm. Repeat the cycle until the cavity depth milling is completed.

[0006] In the above-mentioned method for processing a small-corner structure with a deep cavity in a small area, the three steps S3, S4 and S5 are all fine milling with a single-side allowance of 0.15 mm to 0.2 mm.

[0007] In the above-mentioned method for processing a deep cavity with a small corner structure in a small area, the blade lengths of the short end mill in step S3, the medium-length end mill in step S4, and the long end mill in step S5 are all no longer than 25 mm.

[0008] In the above-mentioned method for processing a deep cavity with a small corner structure in a small area, the shank diameter of the short end mill in step S3, the medium-long end mill in step S4, and the long end mill in step S5 is less than 0.2 mm of the cutting edge diameter.

[0009] In the above-mentioned method for processing a deep cavity with a small corner structure in a small area, in step S7, when the long end mill finishes milling the cavity, the cutting position of the long end mill each time is at the same position as that of each downward feed in the semi-finishing milling in step S6.

[0010] In the above-mentioned method for processing a deep cavity with a small corner in a small area, in step S7, when the long end mill is fine milling the cavity, a cutter allowance of 0.01 mm is left on one side.

[0011] Compared with the existing technology, the advantages of a processing method for a deep cavity with a small corner structure in a small area are: 1. By using multiple tools of different lengths and diameters, combined with reasonable processing steps, such as using 8mm end mills with a total length of 70mm, 100mm, and 130mm in turn during roughing, and precise control of the allowance and feed depth during fine milling (leaving a 0.05mm allowance on one side for semi-fine milling, and a cutting depth of 20mm each time; leaving a 0.01mm allowance on one side for fine milling, and a cutting depth of 15mm each time), the effect of improving processing efficiency and precision is achieved, which can not only quickly remove materials, but also effectively avoid cutting edge connection, making the cavity size more accurate and the surface quality better, meeting the needs of mass production and product assembly.

[0012] 2. By selecting an end mill with a blade length of 25 mm and a shank diameter that is 0.2 mm smaller than the cutting edge diameter, the tool strength is ensured while meeting processing requirements. Through this tool structure design and a reasonable tool use strategy (such as selecting a tool of appropriate length based on the cavity depth), the tool life is extended, the tool replacement frequency is reduced, and the tool cost is reduced. At the same time, a stable tool state also helps to maintain consistency in processing quality.

[0013] 3. The processing method is designed for magnesium alloy materials and the structural characteristics of deep cavities and small corners in small areas, including pre-forming the corners with a 4 mm drill bit, and using a 4 mm extra-long end mill to mill the remaining parts using a forward milling and reverse milling method. This achieves the effect of enhancing processing adaptability, effectively overcomes the processing difficulties of magnesium alloy materials, reduces the tool edge caused by the accumulated errors of machine tools, ensures the stability of product quality, and improves the overall performance and reliability of the product. It is suitable for the processing of such special structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of a magnesium alloy structural part; Figure 2 It is a schematic diagram of the structure of the blank after cutting of magnesium alloy material; Figure 3 It is a schematic diagram of the structure of a tool for processing magnesium alloy materials; Figure 4 It is a schematic diagram of the structure of milling residue when processing magnesium alloy materials. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0016] like Figure 1-Figure 4 As shown, a method for processing a deep cavity with a small corner structure in a small area, the processing method comprises the steps of: S1. Use a 4 mm diameter drill bit to drill four 4 mm holes at the four corners of the magnesium alloy material to form R2 corners; S2. Use a 9 mm drill bit to drill three holes in the cavity at a distance of 0.5 mm from the cavity wall and remove the large excess; S3, use a short end mill with a diameter of 8 mm and a length of 70 mm for roughing, with a processing depth of 40 mm, and a single-side allowance of 0.15 mm to 0.2 mm for fine milling, and the blade length is not more than 25 mm. At the same time, the shank diameter is 0.2 mm less than the cutting edge diameter; S4, use a medium-length end mill with a diameter of 8 mm and a length of 100 mm for roughing, with a processing depth of 70 mm, and a single-side allowance of 0.15 mm to 0.2 mm for fine milling, and the blade length is no more than 25 mm. At the same time, the shank diameter is 0.2 mm less than the cutting edge diameter; S5. Use a long end mill with a diameter of 8 mm and a length of 130 mm for roughing, with a processing depth of 100 mm, and a single-side allowance of 0.15 mm to 0.2 mm for fine milling, and the blade length is no more than 25 mm. At the same time, the shank diameter is 0.2 mm less than the cutting edge diameter; S6. Use a long end mill with a diameter of 8 mm to semi-finish the cavity, leaving a single-side allowance of 0.05 mm, and mill 20 mm in the depth direction each time; S7, use a long end mill with a diameter of 8 mm to finish mill the cavity, milling 15 mm in the depth direction each time, when the long end mill is finish milling the cavity, the cutting position of the long end mill is at the same position as each downward feed of the semi-finishing milling in step S6, and when the long end mill is finish milling the cavity, a single-side cutter allowance of 0.01 mm is left; S8. Use a 4mm long end mill to finish mill the remaining part, using the forward milling and reverse milling method. First, forward milling with a cutting depth of 2mm to 3mm, and then the next forward milling with a cutting depth of 2mm to 3mm. Repeat the cycle until the cavity depth milling is completed.

[0017] The operating principle of the present invention is described as follows: the four small corners (R2) are formed by drilling holes with a 4 mm diameter alloy twist drill, and the inner cavity is first processed by using a 9 mm diameter drill to remove the large excess (see the state after processing). Figure 2 ), and then use three 8mm diameter end mills of different lengths for rough machining (leaving a single-side allowance of 0.15mm to 0.2mm for fine milling of the cavity). Among them, use a tool with a total length of 70mm to machine the cavity to a depth of 40mm, then use a tool with a total length of 100mm to machine the cavity to a depth of 70mm, and finally use a tool with a total length of 130mm to machine the cavity to a depth of 100mm, then use an 8mm diameter end mill for fine milling in the cavity, and finally use a 4mm diameter extra-long end mill to finish the milling residue (see the milling residue Figure 4 ); When using an 8mm diameter end mill to mill the inner wall of the cavity with a 0.15mm to 0.2mm margin, in order to avoid the appearance of a cutting edge along the depth direction, semi-finishing milling and then finishing milling are used. After semi-finishing milling, a 0.05mm margin is left for finishing milling. In addition, during semi-finishing milling, a total of five feeds are made along the depth direction (the cavity is 100mm deep in total), with each cutting depth of 20mm. During finishing milling, each feed along the depth direction is 15mm deep, avoiding the same part as each downward feed of semi-finishing milling, which can play the role of finishing the cutting edge generated during the previous cutting. The rigidity of the 4mm diameter extra-long end mill is worse than that of the 8mm diameter extra-long end mill. The tool yield phenomenon during milling is different from that of the 8mm diameter extra-long end mill, which results in a tool edge. To avoid this phenomenon, when fine milling with the 8mm diameter extra-long end mill, a tool yield margin of about 0.01mm is left on one side to ensure that it is flush with the milling part of the 4mm diameter extra-long end mill. When the 4 mm diameter extra-long end mill mills the residual part, it repeatedly feeds and cuts in the depth direction in a relatively small area. In order to improve cutting efficiency and eliminate the cutting edge caused by the cumulative error of machine tool processing, the milling adopts the method of forward milling and reverse milling, that is, the forward milling method is first used to cut 2 mm to 3 mm in the depth direction, and the reverse milling method is used the next time the tool is fed in the depth direction. This cycle is repeated until the entire depth is cut. It can not only quickly remove material, but also effectively avoid cutting edges, so that the cavity size accuracy is higher and the surface quality is better, which meets the needs of mass production and product assembly.

[0018] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing a deep cavity with a small corner structure in a small area, characterized in that: The processing method comprises the steps of: S1. Use a 4 mm diameter drill bit to drill four 4 mm holes at the four corners of the magnesium alloy material to form R2 corners; S2. Use a 9 mm drill bit to drill three holes in the cavity at a distance of 0.5 mm from the cavity wall and remove the large excess; S3, use a short end mill with a diameter of 8 mm and a length of 70 mm to roughen, and the processing depth is 40 mm; S4, use a medium-length end mill with a diameter of 8 mm and a length of 100 mm to roughen, and the processing depth is 70 mm; S5, use a long end mill with a diameter of 8 mm and a length of 130 mm to roughen, and the processing depth is 100 mm; S6. Use a long end mill with a diameter of 8 mm to semi-finish the cavity, leaving a single-side allowance of 0.05 mm, and mill 20 mm in the depth direction each time; S7, use a long end mill with a diameter of 8 mm to fine mill the cavity, milling 15 mm in the depth direction each time; S8. Use a 4mm long end mill to finish mill the remaining part, using the forward milling and reverse milling method. First, forward milling with a cutting depth of 2mm to 3mm, and then the next forward milling with a cutting depth of 2mm to 3mm. Repeat the cycle until the cavity depth milling is completed.

2. The method for processing a deep cavity with a small corner structure in a small area according to claim 1, characterized in that: In the three steps of step S3, step S4 and step S5, the single-side fine milling is performed with a margin of 0.15 mm to 0.2 mm.

3. The method for processing a deep cavity with a small corner structure in a small area according to claim 1, characterized in that: The blade lengths of the short end mill in step S3, the medium-length end mill in step S4, and the long end mill in step S5 are all no greater than 25 mm.

4. The method for processing a deep cavity with a small corner structure in a small area according to claim 1, characterized in that: The shank diameter of the short end mill in step S3, the medium-length end mill in step S4, and the long end mill in step S5 is 0.2 mm smaller than the cutting edge diameter.

5. The method for processing a deep cavity with a small corner structure in a small area according to claim 1, characterized in that: In step S7, when the long end mill is finishing milling the cavity, the cutting position of the long end mill each time is at the same position as that of each downward feed of the semi-finishing milling in step S6.

6. The method for processing a deep cavity with a small corner structure in a small area according to claim 1, characterized in that: In step S7, when the long end mill is used to finish mill the cavity, a cutter allowance of 0.01 mm is left on one side.

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